Mushkin's new XP-800 AP power supply is a well rounded high quality product that seems to be positioned exactly the right way. It is not too big (1200W), which would make it too expensive and its also not too weak (450W), which would people make think "Oh I need more". In reality most gamers would be fine with a high-quality 450W power supply. Since a lot of crappy PSU makers overrate their PSUs it has become current practice to just assume about double the power draw for your system to be on the safe side. On the other hand a nice quote that I saw today from the great JonnyGuru says "We don't all drive cars that can do 120 MPH so we can drive 120 MPH.". I do, I'm German. Anyway... where was I?
In our testing we saw the XP-800 AP deliver very good voltage stability results. Also the efficiency was top notch with over 84%. Presentation of the PSU is fine as well with its glossy dark paint.
I did not find any difference in the RailFusion feature, but it could become handy should you ever need to pull more than 20A from a single 12V rail. The current price at Mushkin.com seems well justified, the $219 at NewEgg are a tad bit high in my opinion. The main reason for not giving a higher score is that the fan noise is louder compared to other similar offerings from the competition, even though it is not "loud".